The overall goal of the project is to identify and characterize macrophage products of potential importance in immune and inflammatory responses in order to manipulate these responses for clinical benefit. This laboratory identified mouse and human Mig and mouse Crg-2, previously undescribed members of a family of small secreted proteins, termed chemokines. Crg-2 is the murine analogue of the human chemokine IP-10. Mig and Crg-2/IP-10 are inducible in macrophage and other cells by IFN-gamma and target activated T cells, B cells and NK cells through the CXCR3 receptor.The chemokines are members of an expanding family of chemotactic factors, now numbering more than 30, that are thought to be critical for the trafficking of leukocytes in both homeostasis and in inflammatory reactions. Most recently, chemokines and their receptors have been found to be of central importance in HIV disease, since some chemokine receptors are used by HIV to enter cells and some chemokines are able to suppress HIV infection by inhibiting HIV entry. We have expanded this project beyond Mig and Crg-2/IP-10 to include studies of chemokines generally in their activities on lymphocytes, and studies of coreceptor use by HIV and SIV, including investigations of signalling by HIV envelope glycoproteins through chemokine receptors. In one part of this project, we have refined a flow cytometric assay for calcium fluxes that allows for simultaneous phenotypic analysis of responding cells, and we have used this assay to investigate responses of lymphocytes to a large collection of chemokines, correlating signalling with chemokine receptor expression. We have used this assay system to analyze chemokine receptor expression and function on cells from thymus and tonsil, in addition to peripheral blood lymphocytes. In collaboration with members of Anthony Fauci?s laboratory, we have also applied the flow cytometer assay to studies of signalling by HIV envelope glycoproteins (Envs) through chemokine receptors. - Chemokine, chemotaxis, calcium, lymphocytes, HIV, SIV